1. Field of the Invention
The present invention relates to a method for power management and particularly to power management of a smart phone having two subsystems, a mobile phone, and a Personal Digital Assistant (PDA), which achieves long battery life and reduces unnecessary power loss due to system operation.
2. Description of the Prior Art
The development of manufacturing techniques for mobile phones and PDAs has resulted in significant improvements in size and cost, adding to the popularity of these devices. Moreover, to better serve users with a greater need for mobility, smart phones, a combination of the PDA and mobile phone, have become commercially available. Smart phones combine mobile telephony and PDA functionality in a single device.
Smart phones combine two sub-systems, the PDA and the mobile phone, sharing one battery, and therefore require efficient power management to reduce unnecessary power consumption and extend battery life. Traditionally, however, power management is dedicated to the PDA or mobile phone only. Single system power management is inefficient for a smart phone having two sub-systems. It is impossible for example, to engage the mobile phone the PDA sub-systems simultaneously. The traditional power management system, however, allocates full power to both sub-systems, even if full power is only required by one sub-system.